Giant drill ready to dig Lee ‘super sewer’ 240ft below East London

A 300ft long tunnelling ‘worm’ that will drill the first part of London’s ‘super sewer’ has been switched on for the first time.

The giant drill, measuring 40ft high with a 25ft diameter cutting blade, starts digging a four-mile sewer tunnel under East London next month.

The hand-over at the German plant where it has been built was the first and last time the machine will be seen before being taken apart.

It will be shipped to Tilbury next month to be reassembled at Beckton sewage works where it will start tunnelling 240ft below ground to reach Abbey Mills pumping station four miles away.

But transporting the giant drill even from Tilbury is a major headache.

It will be brought in pieces overnight by lorry along the A13 to be reassembled at Beckton sewage works 240ft below ground.

Even in pieces, the equipment is so wide that Thames Water needs to move lamp posts temporarily and other obstacles on nearby streets.

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“Tunnelling is a risky business, especially on this scale,” said Thames Water’s Lawrence Gosden.

“We face the challenge of boring the deepest tunnel in London at some of the highest groundwater pressures that a machine of this type has tunnelled in, drilling through four miles of the most abrasive ground without any shafts along the way.”

The �635 million Lee Tunnel will be Britain’s deepest tunnel ever. Its aim is to prevent 16 million tonnes of sewage entering the Lea river each year, resulting from London’s Victorian sewers not being big enough any more to cope with urban expansion and heavy rainfall. Abbey Mills has London’s largest overflow, 40 per cent of the total sewage discharge.

The next phase of London’s ‘super sewer’ scheme is the proposed Thames sewage tunnel winding its way below the riverbed from the Isle of Dogs to Chelsea.

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